(Adds Pfizer/BioNTech comment)

BRUSSELS, April 9 (Reuters) - The European Commission is seeking EU governments' approval to launch talks with Pfizer and BioNTech for the purchase of up to 1.8 billion doses of their COVID-19 vaccines to be delivered in 2022 and 2023, an EU official told Reuters.

Earlier on Friday, German daily Die Welt reported that the Commission was shortly to sign contracts to buy up to 1.8 billion doses, but did not say with which company.

The EU official, who asked not to be named because the matter is confidential, said the EU executive had already decided to approach Pfizer-BioNTech and that EU governments backed the plan, though there was not yet a definitive approval.

A Commission spokesman confirmed plans to buy the additional doses, of which half would be optional.

He also confirmed that the EU executive had already identified one supplier, a manufacturer of mRNA vaccines, but declined to comment on which company would be approached to negotiate the contract.

"If provided the opportunity Pfizer and BioNTech are prepared to supply Europe with hundreds of millions of doses of COVID vaccines in 2022 and 2023 produced in our manufacturing facilities in Europe," a Pfizer spokesman said.

The two companies have the capacity to produce more than 3 billion doses of vaccine in 2022, he added.

Pfizer-BioNTech and Moderna are already supplying the EU with mRNA vaccines and German biotech firm CureVac is seeking EU approval for its mRNA shot.

The vaccines would be delivered under monthly timetables and with clauses obliging the supplier to deliver, the EU official said. (Reporting by Francesco Guarascio @fraguarascio Additional reporting by Caroline Copley Editing by Mark Heinrich)